Change is the one constant in Silicon Valley, as reflected in this year's edition of the SV 150 list of the region's biggest tech companies. It often seems the story of Silicon Valley firms takes one of two forms: Company surprises with innovation outside its core products, or former superstar attempts a comeback. There were plenty of both in 2013.

With SpaceX, the advanced rocket company he founded outside of Los Angeles in 2002, billionaire and Tesla CEO Elon Musk hopes to employ recyclable rockets to save humanity from itself, blasting astronauts into outer space to one day build settlements on Mars.

Silicon Valley technology companies produced record profits in 2013, but much of that cash was pushed into bank accounts and returned to investors at a level never before seen in the region’s iconic industry.